fix(inbounds): allow negative subSortIndex for subscription order (#6465)

* fix(inbounds): allow negative subSortIndex for subscription order

Preserve explicitly set negative indices so primary inbounds can sort
ahead of the default without renumbering peers; keep 0/omitted → 1.

* fix(inbounds): gofumpt model.go and trim subSortIndex comments

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Co-authored-by: mrchatam <287639636+mrchatam@users.noreply.github.com>

frontend/src/schemas/forms/inbound-form.ts

@@ -80,7 +80,7 @@ export const InboundDbFieldsSchema = z.object({
   nodeId: z.number().int().nullable().optional(),
   shareAddrStrategy: ShareAddrStrategySchema.default('node'),
   shareAddr: z.string().default(''),
-  subSortIndex: z.number().int().min(1).default(1),
+  subSortIndex: z.number().int().default(1),
   disableFlow: z.boolean().default(false),
 });
 export type InboundDbFields = z.infer<typeof InboundDbFieldsSchema>;